Repeater system



Ju1y21,1942. 7 G, NER V 2,290,335

REPBATER SYSTEM Filevd Aug. 3, 1940 2 Sheets-Sheet 1 /m'bYU/' 5252777.71.577527 1145,

July 21, 194.2. G. KINER 2,290,335

REPEATER SYSTEM Filed Aug. 3, 1940 2 sheets-sheet 2 Patented July 2l,1942 29ans REPEATER SYSTEM Glenn Kiner, Harvey, Ill., assigner toKellogg Switchboard and Supply Company, Chicago, Ill.,

a corporation of Illinois 8 Claims.

The invention relates, in general, to a telephone system forinterconnecting lines terminating at a central station and moreparticularly to a system of the cordless type in which connectionsbetween the various lines are made by the use of connecting keysassociated with connecting circuits for interconnecting the lines ascalling and called lines.

The lines radiating from a central point, such as a dispatchers station,are usually of varying length. In a system of this type, the practice ofincluding a gain control and balance network in the line circuit, withwhich each line is equipped, permits adjustment to the respective valuesof the lines, is well known, and in conjunction with a, repeaterprovides the needed energy to overcome the transmission losses on longlines.

An object of this invention is the provision of a line circuit and aconnecting circuit arrangement in which relay means are providedcontrolled by the position of the connecting keys for including orexcluding the gain control and balance network and repeater in aconnection between lines as calling and Vcalled lines depending uponwhether it is a connection between a long haul line and a short haulline or two short haul lines.

Another object of the invention is the provision of relay means in theline circuit which is operated by current received from either linewhile a connection remains in service to operate a disconnect signal orlamp to indicate to the attendant a disconnect or recall signal byeither line of an existing connection.

Another object of the invention is the provision of relay means whichremain normal to include a repeating coil in circuit between lines ascalling and called lines when the connecting keys are positioned toexclude the balance network and repeater when connecting short haullines as calling and called lines.

The above features, as well as others not specifically pointed outabove, will be more fully pointed out in the following description takenin connection with the accompanying drawings comprising Figs. 1 and 2,taken together.

Fig. 1 illustrates a line circuit LC, there being one such line circuitfor each line in the system and includes a repeating coil RC, a ringingrelay RI which, when operated, connects ringing current to the calledline from a ringing current source RS. A ring-up relay RU is actuated bythe incoming signal from a calling line to operate a line relay LR whichcloses a circuit to light a line lamp signal LS. A supervisory relay SRaffected when an incoming signal is received from either a calling orcalled line while the connection between substations remains in servicecontrols the lighting of a disconnect lamp signal DS to indicate arecall or disconnect signal to the operator. A disconnect relay DR isprovided and controls the elacement of the line lamp signal LS and alsodisconnects the operators leads from the line circuitLC. A connect relayCR is also provided which, when operated, connects the gain control padGP and balance network BN into the circuit when a connection being setup between a calling and called line Vnecessitates the use of a repeateras will be more fully hereinafter described.

Fig. 2 illustrates' the key circuit arrangement KC which comprisesconnect keys CK, CK' and CK2 associated, respectively, with lines A, Band C shown in the drawings. The keys CK, etc, are used to establishconnections between the lines of the system as calling and called linesand are of the two-position locking type for purposes as will be morefully hereinafter described. A connect control relay CC common to thekeys CK, CK and CK2 is controlled by the operation or" the keys whenmoved to establish a connection between a calling and called line. Arelay connector link circuit RL shown below the dash line in Fig. 2comprises connect relays CO, CO and CO2 which are associated,respectively, with the lines A, B and C. A switching relay SW associatedwith the connector link RL, when operated, connects a suitable repeaterof any well known type (as for example the one shown in U. S. Patent2,050,292 to Eaton) which terminates at the terminals L, L', L2, L3, L4and L5 of the connector link RL. The position of the keys CK, etc.,control the operation of the switching relay SW when establishing aconnection between a calling and a called line and determines theinclusion or exclusion of a repeater in the connection. A non-ringthrough repeating coil RC is also provided which remains connectedbetween the calling and called lines when the relay SW does not operate.

Assuming that the system, as above outlined, requires lve such links RLto take care of the trafl'ic between the lines of the system, a key CKis repeated for such link RL, and therefore, each line will be equippedwith live such connect keys.

Having described, in general, the apparatus which comprises theinvention, a more detailed description of the invention will be given bytracing the operation of the system in establishing a connection betweena calling and a called line.

The subscriber at the calling substation associated with the line A uponthe initiation of a call operates the hand generator thereat and.current therefrom operates the ring-up relay RU of the line circuit LCassociated with the calling line. The closing of front contact 2 of therelay RU operates the line relay LR from battery through the relaywinding, back Contact of the disconnect relay DR, armature 3, conductor4 to ground at front contact 2. Relay RU restores at the conclusion ofthe current fromV the calling station and the opening of its frontcontact 2 opens the initial energizing circuit of relay LR but the relaylocks up through its front contact 5, conductor 6 to ground at backcontact 1 of relay DR. The

closing of back contact 2 oi relay RU closes a circuit for line lampsignalv LS, traced from battery through the signal LS conductor 8, frontcontact 9 of relay LR to ground, at back contact 2 of relay RU. The linesignal LS is lighted and the operator noting the signal actuates thelistening key LK associated with the calling line to connect heroperators set OS over conductors 9 and I0, front contacts II and I2 ofthe listening key LK, conductors I3 and I4 to the tip and ringconductors T and R of the line circuit LC through the back contacts I5and I8 of the disconnect relay DR. The operator is now connected to thecalling line and upon receiving the number of the Wanted line,determines whether the connection between the calling substation and thecalled substation necessitates the use of a repeater in the connection.

Assuming that the connection to be established with the called linenecessitates a, repeater and that the called line is the line B, theoperator vactuates the connect key CK associated with the calling lineand the connect key CK associated with the called line to move them tothe left or repeater connection position E. The closing of front contactI1 of the key CK operates the disconnect relay DR from battery throughrelay DR, conductor I8 to ground at front contact I1 of the key CK.Relay DR operating over this circuit opens the locking circuit of therelay LR at its back Contact 1 and relay LR restoring opens its frontcontact 9 to efface the line signal LS and the opening of back contactsI5 and I8 of the relay DR disconnects the operators listening leads I3and I4 from the tip and ring conductors T and R of the line circuit LC.

The connect control relay CC associated with the key group, comprisingconnect keys CK, CK and CK2, is a marginally operated relay and requiresthe current from both` resistance R and R connected in multiple for itsoperation. The circuit through resistance R is traced from batterythrough relay CC, conductor I9, front contact 28 of key CK, conductor 2Ito ground through the resistance R. The circuit through the resistanceR' is traced from battery through relay CC, conductor I9, front contact22 of the key CK conductor 23 to ground through the resistance R'. Therelay CC is thus connected in multiple with the resistances R and R' andoperates when two keys of the connecting circuit have been operated toclose its front contact 24 to operate the network connect relay CR, frombattery through the winding of relay CR of the line circuit LCassociated with the calling line, conductor 25, front contacts 25 and 21of relay CK, conductor 28 to ground at front contact 24 of relay CC. Therelay CR closes its front contacts 29, 38, 3| and 32 to connect the gaincontrol pad GP into the line circuit LC of the calling line. The groundat front contact 24 of relay CC also extends over conductor 28, throughfront contacts 33 and 34 of the key CK and over conductor 35 to therelay CR of the line circuit associated with the called line andoperates to close its iront contacts to connect the gain control padinto the circuit. Relay DR of the line circuit of the called line isalso operated by the closure of the front contact 35 of the connect keyCK.

The ground at front contact 24 of the relay CC also energizes theconnecting relays CO and CO' associated with the keys CK and CK. Thecircuit for relay CO extends from ground at contact 24 over conductor28, front contact 21 of the key CK, conductor 31 to battery through therelay CO and the circuit of relay CO extends through front contact 33 ofthe key CK and conductor 38 to battery through relay CO'. The switchingrelay SW is also operated from battery through relay SW, conductor 48,front contact 4I of the key CK, conductor 31, front contact 21 of thekey CK, conductor 28 to ground at front contact 24 of relay CC. Havingpreviously assumed that the connection between the calling and calledlines necessitated a repeater connection, the closing of front contacts44 and 45 of relay SW connects one side of the repeater, connected toterminals L and L through front contacts 44 and 45 of relay SW, frontcontacts 46 and 41 of the connect relay CO and conductors 48 and 48 tothe front contacts 30 and 3| of the relay RC of the line circuit LC ofthe calling line. The conductor 48 extends through the front contact 30,the windings R3 and R4 of the gain control pad GP, the front contact 29of relay CR to the tip conductor T. The conductor 49 extends through thefront contact 3| of the relay CR, the windings R5 and R6 of the gaincontrol pad GP, front contact 32 of the relay CR to the ring conductorR. The closing of front contacts 50 and 5I of the relay SW associatesthe other side of` the repeater from terminals L2 and L3, through frontcontacts 50 and 5I, conductors 52 and 53, front contacts 54 and 55 ofthe relay CO, conductors 56 and 51, front contacts 58 and 59 of therelay CO to conductors 6) and 6I which extends through front contacts ofthe relay CR of the line circuit associated with the called line,windings of the gain control pad of the said line circuit to the tip andring conductors of the same.

The operator having connected the calling line A with the called line Bthrough the medium of the keys CK and CK', the ringing key RK associatedwith the called line is now operated by circuit ground, from the frontcontacts 62 and 63 of the ringing key RK actuates the ringing relay RIof the line circuit associated with the called line. Relay RI operatesand closes its front contacts 64 and 65 to connect ringing current fromthe ringing current source RS to signal the subscriber on the calledline B. The restoration of the ringing key RK opens the circuit of therelay RI which restores and disconnects the ringing current source RS.The called subscriber, in response to the call signal, removes thereceiver and the talking circuit between the calling and calledsubstations may be traced over the heavily marked conductors.

Upon the termination of conversation, the subscribers replace theirrespective receivers and actuate the hand generators to set up thedisconnect lamp circuit to give the operator an indication that theconversation has terminated. Current from the calling line againoperates the ring-up relay RU to close its front contact 2 to operatethe supervisory relay SR, from battery through relay SR, conductor 66,front contact 3 of relay DR and conductor 4 to ground at front Contact2. Relay SR locks up from battery through relay SR, its front contact51, to ground at front contact 1 of relay DR. Relay RU deenergized whencurrent from the calling substation ceased to close a circuit for thedisconnect lamp signal DS from battery through the lamp DS, frontcontact 68 of relay SR, back contact 9 of relay LR to ground at backcontact 2 of relay RU. Current from the called line operates the relayRU of the line circuit LC associated with the called line to light thedisconnect signal DS in the same manner as just described. The lighteddisconnect lamp signals DS of the calling and called lines indicate tothe operator that conversation has terminated and the restoration of theconnect keys CK and CK now takes place.

The restoration of the connect key CK interrupts the circuit of therelay CC at the front contact 2l! and the opening of front contact 24 ofrelay CC restores the switching relay SW, the connect relays CO and COand the relay CR. The opening of front contact l1 of the key CK restoresrelay DR and the opening of front contact 1 of relay DR allows relay SRto restore which effaces the lamp signal DS at its front contact 68.'I'he restoration of the connect key CK' restores the relay DR of theline circuit associated with the called line at its front contact 36 toeace the disconnect signal DS due to the restoration of the relay SR andrelay CC, hav# ing restored, the connect relay CR is also restored. Theapparatus used in establishing the connection, as above set forth, isnow at normal and again available for establishing other connections.

The description between a calling and called line where it is notnecessary to use a repeater, gain control pad and balancing network inthe connection will now be described. Assuming that such a connection isto be established between the line A as a calling line and the line B asa called line, theconnect keys CK and CK' are moved to the right or theposition F. The operation of the circuit is the same as previouslydescribed, but the energization of the relays DR of the line circuitsassociated with calling and called lines are operated through frontcontacts 69 and 'FS of the actuated keys CK and CK. Relay CC is alsooperated through the resistances R and R' in multiple but the circuitsextend through the front contacts 'H and 'l2 of the keys CK and CK andrelays CO and CO are also operated to ground at contact 2li through thefront contacts 13 and 14 of the keys CK and CK. No energizing circuitfor the switching relay SW of the link RL and relays CR of the linecircuits, associated with calling and called lines, is closed as thecircuit closing contacts which control the operation of these relayswhen the keys CK and CK' are in position E are not a part of the keycontact arrangement when in its F position. The switching relay SWremaining normal, the repeating coil RC remains in the talking circuitbetween the calling and called lines through the back contacts 44, t5and 50, 5I of the relay SW and as relays CR of the respective linecircuits associated with the calling and called lines remain at normalthe repeating coil is connected through normal contacts 29 and 3l of therelay CR to the tip and ring conductors of the respective line circuits.The repeating coil is of the non-ring through type and prevents ringingcurrent from one line from operating the relay RU of the other line asis well understood. The disconnect signals DS of the respective callingand called line circuits are controlled in the same manner anddisconnection of the lines as calling and called lines and therestoration of the apparatus used in establishing the connection is thesame as previously described.

Having thus described my invention, what I claim is new and desire tosecure by United States Letters Patent is:

1. In a cordless type telephone system the combination of line circuitsand a connecting circuit, amplier means including a g-ain control meansand a balancing network, keys for connecting said circuits, relay meansin said circuits acting in response to the position of said keys toinclude or exclude said amplier means from said circuits, a repeatercoil, and relay means arranged to include said coil in the circuit whenthe said relays are operated so as to exclude the sai-d amplifier.

2. In a cordless type telephone station system the combination of linecircuits and a connecting circuit, amplier means including a gaincontrol means and a balancing network means, keys for connecting saidcircuits, and relay means in said circuits acting in response to theposition of said keys to include ysaid amplifier means in, or exclude itfrom said circuits.

3. In a cordless type telephone system the combination of line circuitsand a connecting circuit, a gain control means and a balancing networkmeans, arranged to be connected in said line circuit, and repeatermeans, adapted to be included in said circuit, connecting keys forconnecting said circuits, and relay means in said circuits acting inresponse to the action of said keys to include said gain control andbalancing network means in, or exclude it from said circuits.

4. In a telephone system, line circuits, a connecting circuit, keys insaid connecting circuit, one for each line circuit, amplifier means,relay means for connecting said pair of line circuits and including insaid connection said amplifier means, a circuit for actuating said relaymeans controlled at contacts of said keys corresponding to the connectedlines, and means whereby said relay means is notJ operated until the twokeys are actuated.

5. In a cordless type telephone system the combination of line circuitsand a connecting circuit, amplier means including a gain control meansand a balancing network means, keys for connecting said circuits, arepeating coil, relay means in said circuits acting in response to theposition of said keys to include or exclude said means from saidcircuits, and when excluding said ampliier means to include said coil.

6. In a cordless type telephone system the combination of a line circuitand a connecting circuit, ampliier means including a gain control meansand a balancing network means, keys for connecting said circuits, andrelay means in said circuits acting in response to said keys to includesaid amplifier means in, or exclude it from the connected circuits.

7. In a telephone system, line circuits, a connecting circuit, variablyoperable keys in said connecting circuit, one for each line circuit, am-

plier means, a repeater coil, relay means acting 'in response to theposition of the said keys corresponding to a pair of line circuits forconnecting said pair of line circuits and including in said connectionsaid amplifier means, or excluding said amplier means and including saidrepeater coil according to the position of said keys.

8. In a telephone system, line circuits, a connesting circuit, variablyoperable keys in said connecting circuit, one for each line circuit, am-10

